The invention relates generally to coke oven batteries. Of particular interest to the invention is an arrangement for changing the heat supply to the ovens of a coke oven battery from a condition of extreme heating, that is, a condition in which large quantities of heat are supplied to the ovens, to a condition of lesser or no heating, that is, a condition in which smaller quantities of heat are supplied to the ovens or in which no heat is supplied to the ovens, as well as for changing the heat supply in the opposite sense.
An arrangement for changing the heat supply to the ovens of a coke oven battery is known and includes a control linkage which extends around the battery. This control linkage is operative for changing the flow of air and hot waste gases, as well as for regulating the supply of combustion air, via air inlet valves and waste gas throttle valves which may be in the form of butterfly valves. The arraangement includes a further control linkage which operates a three-way valve provided for the decarbonizing air.
The reason that it is desirable to be able to change the heat supply to the ovens of a coke oven battery is based on the finding that savings of up to 10 percent in heating costs may be realized when, instead of providing a constant heat supply for the ovens as has been the conventional practice, the heat supply is adjusted to the state of coking of the charge by so-called programmed heating. Such adjustment of the heat supply consists in that coking of the coal is carried out using a large heat supply at the beginning of the coking operation with the heat supply being reduced towards the end of the coking operation. The regulation of the heat supply may be effected by means of a control program which operates via fuel gas and air valves, as well as waste gas valves and throttling flaps, provided for each heating wall of the coke oven battery. This control program requires relatively large expenditures for the measuring and regulating mechanisms which are necessary.
With respect to the savings in heating costs, it is especially significant that an effective heating program need not provide particularly fine control over the heat supply during the entire duration of the coking period. The reason resides in that the thermal response of an oven system is generally quite sluggish. In fact, it has been found to be adequate when phases of extreme heating alternate with phases of no heat supply whatsoever. Here, the periods for which the heat supply is interrupted become longer as the coking operation progresses.
Although the known programmed arrangements for changing the heat supply operate reasonably satisfactorily, they possess the disadvantage mentioned earlier, namely, that they require large expenditures for the measuring and regulating mechanisms which are necessary.